Made a similar test with the following Bird elements
and a test setup consisting of:
RF source adjustable to 50 and 100W output monitored on a freshly calibrated
HP410C RF voltmeter with
the T- junction and also connected via a Collins 302C-3 wattmeter to a Bird
250W dummy load.
Test frequency: 1600 kHz
Power level 50 W Reading on 50H 45W
Power level 100 W Reading on 100H 90W
Power level 100 W Reading on 250H 85W
Power level 100 W Reading on 500H #1 80W
Power level 100 W Reading on 500H #2 80W
additionally a check of a 1000P (450 kHz to 2500 kHz) element was made
Power level 100 W Reading on 1000P 85W
Comparison test:
Test frequency: 2000 kHz
Power level 50 W Reading on 50H 47W
Power level 100 W Reading on 100H 95W
Power level 100 W Reading on 250H 85W
Power level 100 W Reading on 500H #1 85W
Power level 100 W Reading on 500H #2 80W
additionally a check of a 1000P (450 kHz to 2500 kHz) element was made
Power level 100 W Reading on 1000P 80W (!)
The readings are within the +/- 5% of full scale promised except on the 50H and
100H elements, where
they are about 10% low.
It appears that the lower frequency limit, as expected, is less sharply
defined on the higher power elements.
The Collins wattmeter, incidentally, read 70 and 130 W respectively...
73/
Karl-Arne
SM0AOM
----- Original Message -----
From: "Mark Hill" <g4fph@mjha.co.uk>
To: "Amps Reflector" <amps@contesting.com>
Sent: Tuesday, March 29, 2005 7:51 PM
Subject: Re: [Amps] Bird 'H' series inserts: Performance on 160
> Gary,
>
> Aah! That's where the 'rough science' part comes in. I used my Jap. Daiwa
> (that is at least spec'd down to 1.8 MHz) as reference! Actually the Daiwa
> correlates quite well against the Bird on HF. Perhaps Bird use these to do
> their production cal. against ;-)
>
> I was expecting the 250H to exhibit a bit more (some) droop than the 2500H,
> but couldn't really discern any. Perhaps a 50H would show some?
>
> Regards.
>
> Mark.
>
> -------------------------------------------
> At 17:38 29/03/2005, you wrote:
>
>
> >Mark Hill wrote:
> >>Anyway, to get back to somewhere near where this thread started. I did
> >>some rough science checks on a 250H Bird 43 insert. I did not find that
> >>using it resulted in readings that were dramatically low just below 2
> >>MHz. I checked down as far as 1.6 MHz and would say that any additional
> >>error from using it at frequencies down to this far below its lower limit
> >>was negligible.
> >>My personal conclusion therefore is that both 250 Watt and 2500 Watt 'H'
> >>series elements are good to go on topband. If anyone has other 'H'
> >>series ones, I would be interested in any results they collect.
> >
> >What method did you use to measure power to compare the bird to?
> >
> >Note that the higher power the element the broader band it is. Don't
> >expect the 250H to be the same as the 2500H.
> >
> >73
> >Gary K4FMX
> >
> >
>
> *******************************************
> Mark Hill - G4FPH
> E-mail: g4fph@mjha.co.uk
> Current web pages at: www.qsl.net/g4fph
> Old web pages at: www.g4fph.freeserve.co.uk
> -------------------------------------------
> Dipoles resonant on 1942/3695/7065 kHz
> 2 ele delta loop beam resonant on 14180 kHz
> -------------------------------------------
> Remember - SIDE for HV safety:
> S witch off
> I solate
> D ump
> E arth
> *******************************************
>
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Anti-Virus.
> Version: 7.0.308 / Virus Database: 266.8.4 - Release Date: 2005-03-27
>
>
--
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.308 / Virus Database: 266.8.4 - Release Date: 2005-03-27
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|